Rotor for a rotary piston engine



Jan. 13, 1970 F. FEND ROTOR FOR A ROTARY PISTON ENGINE Filed May 23, 1968 United States Patent O 3,489,125 ROTOR FOR A ROTARY PISTON ENGINE Fritz Feud, Regensburg, Germany, assignor to Fichtel & Sachs A.G., Schweinfurt, Germany Filed May 23, 1968, Ser. No. 731,560 Claims priority, application Germany, June 3, 1967 F 52,598 Int. Cl. F01c 21/08 US. Cl. 123-8 8 Claims ABSTRACT OF THE DISCLOSURE The rotor body of a rotary-pistonvengine is a lightmetal pressure casting in which the central opening, radial slots for apex vanes, grooves in the end walls for arc-shaped segmental rings, and axial bores for rivets are formed in the casting operation. Annular steel plates are partly recessed in the end walls and fastened by the afore-mentioned rivets. They project partly into the central opening to secure the rotor on an eccentric received in the opening and carry a gear rim and a cylindrical supporting face respectively.

BACKGROUND OF THE INVENTION This invention relates to improvements in rotarypiston engines, and particularly to an improved rotor for such engines.

The orbiting rotor of the known engine has a central opening and three circumferential flanks angularly offset about the axis of the rotor between two opposite end faces of the same which are transverse of the axis. The flanks meet in axial apex edges in which slots for radial sliding vanes are formed. Plugs on the ends of the vanes are received in enlarged end portions of the slots. Grooves in the end faces connect respective pairs of the enlarged end portions and normally receive arc-shaped segmental piston rings.

The rotors employed heretofore are rather complex pieces of machinery which are manufactured at relatively high cost, the several flanks, slots, grooves, and openings being formed by machining from solid metal.

The object of the invention is the provision of a rotor for a rotary piston engine which can be mass-produced at low cost and requires but a minimum of machining operations.

SUMMARY OF THE INVENTION With these objects and others in view, as will hereinafter become apparent, the invention provides a rotor of the type described whose main portion is a unitary, pressure-cast body of light metal formed with the slots and grooves in the casting operation. Respective face portions of the body constitute the rotor flanks and annular portions of the rotor and walls contiguously adjacent the flanks.

Other features, additional objects, and many of the attendant advantages of this invention will readily be appreciated as the same becomes better understood by reference to the following detailed description of a preferred embodiment when considered in connection with the appended drawing.

BRIEF DESCRIPTION OF THE DRAWING In the drawing:

FIG. 1 is a fragmentary axial end view of a rotor of the invention; and

FIG. 2 shows the rotor of FIG. 1 in section on the line II-II.

3,489,125 Patented Jan. 13, 1970 DESCRIPTION OF THE PREFERRED EMBODIMENT Only as much of a rotor for a rotary piston engine is shown in the drawing as is needed for an understanding of the invention, and the remainder of the engine which does not form part of the rotor has been omitted. The engine will be understood to be of the well-known type shown, for example, in VDI-Zeitschrift, vol. 102, No. 8, page 319, FIGS. 12 and 13 (March 11, 1960).

As is conventional, the illustrated rotor is approximately triangular and has a central, axial opening. Its main part is a body 1 of diecast aluminum alloy which constitutes the three outwardly bulging flanks of the rotor and the annular portions of its radial end walls 3, 4 contiguously adjacent the flanks. Where the flanks meet, they define apex edges in which slots 5 are formed in the diecasting operation.

The slots 5, which extend radially inward of the rotor body 1, normally receive non-illustrated sealing vanes and springs which bias the vanes outward of the slots toward the engine casing (not shown). Sealing plugs on the vanes are normally received in the enlarged end portions 6 of the slots 5 near the end faces 3, 4. Grooves 2 in the end faces extend between end portions '6 and normally receive arc shaped segmental piston rings which provide seals between the end faces and corresponding radial walls of the non-illustrated engine casing. The grooves 2 also are formed in the casting operation.

The body 1 has two annular axial recesses 7 of identical size and shape about the orifices of the central rotor opening in the two end walls. Three axial bores 8 which terminate in the two recesses 7 and shallow pockets 9 in the three flanks of the rotor, which control the shape of the combustion chambers in the engine, are also present in the cast body 1 when it emerges from its mold and do not require secondary machining. Some finishing by mechanical operations is normally required on the cylindrical wall 10 of the body 1 which radially bounds the central rotor opening and provides a bearing face for a non-illustrated eccentric.

The orifices of the central opening in the side walls 3, 4 are marginally obstructed by projecting inner portions of two flat, annular steel plates 11, 13 whose outer portions are conformingly received in the recesses 7. The inwardly projecting portion 12 of the plate 11 forms a gear rim whose teeth are directed toward the rotor axis and mesh with a non-illustrating pinion on the engine casing in the usual manner during operation of the engine. The inner cylindrical face 14 of the plate 13 requires machining to a precisely circular configuration if it is to serve as a guide and support for the rotor in cooperation with a non-illustrated element on the engine casing. The two projecting inner rims of the plates 11, 13 axially confine the conventional eccentric, and thereby help to maintain the proper axial position of the rotor.

The plates 11, 13 are stampings of identical outer configuration. The teeth of the gear rim 12 may be formed in the stamping operation or they may be broached after stamping. The plates are attached to the cast rotor body 1 by three tubular rivets 15 which are received in the three bores 8 respectively and pass through aligned apertures 17 in lugs 16 of the plates 11, 13. The lugs 16 are ofiset on each plate, and project from the main portion of the associated plate toward the apexes of the rotor.

FIG. 1 shows the provisionally assembled rotor without the rivets 15. The rivets are inserted and upset in the manner shown in FIG. 2 only after the rotor has been installed on the eccentric.

The rotor shown in the drawing thus consists of a l ight metal pressure casting and of two flat stamped steel plates. As cast, the body 1 is formed with the grooves 2, the slots 5 having enlarged end portions 6, the annular recesses 7, the bores 8 for the rivets 17, and the pockets 9. It needs machining only on the cylindrical bearing face 10. The plate 11 requires little finishing, if any, if the teeth of the integral gear rim 12 are also stamped. The inner cylindrical face 14 of the plate 13 must be given a smooth and precisely cylindrical shape, but this is not needed if the rotor is'not guided on this face.

The rotor proper of the invention thus can be produced at low cost since it requires very little machining.

What is claimed is:

1. In a rotor for a rotary piston engine, the rotor having an axis and a central axial opening adapted to receive an eccentric, two opposite end faces transverse of said axis, a plurality of angularly offset circumferential flanks axially extending between said end faces, each flank defining an axial apex edge of said rotor with each circumferentially adjacent flank, each apex edge being formed with a slot extending between said end faces and inward of the rotor in an approximately radial direction, the end portions of each slot adjacent said end faces being enlarged, said end faces being each formed with a plurality of grooves, each groove connecting respective enlarged end portions of two of said slots, the improvement which comprises:

(a) a unitary, pressure cast body of light metal constituting a portion of said rotor,

(b) said body being formed with said slots and with said grooves,

(c) respective face portions of said body constituting said flanks and annular portions of said end Walls contiguously adjacent said flanks.

2. In a rotor as set forth in claim 1, said central opening having an orifice in each of said end walls, one of said annular end wall portions being formed with an axial recess about the orifice of said opening in said one end wall, an annular steel plate, a portion of said plate being conformingly received in said recess, and a gear rim on said plate having a plurality of teeth directed toward said axis.

3. In a rotor asset forth in claim 2, said gear rim being i an integral portion of said steel plate.

4. In a rotor as set forth in claim 2, said body being formed with a plurality of axial bores therethrough terminating in said recess and angularly spaced from each other relative to said axis, said plate being formed with a plurality of apertures respectively axially aligned with said bores, and a rivet received in each bore and the aligned aperture, and fastening said plate to said body.

5. In a rotor as set forth in claim 2, the other annular end wall portion being formed with an axial recess about the orifice of said opening in said other end wall, another annular steel plate, a portion of said other plate being conformingly received in the last-mentioned recess, said other plate having a cylindrical inner face about said axis.

6. In a rotor as set forth in claim 5, said recesses being substantially identical in shape and size, and said plates having respective outer rims of substantially identical shape and size.

7. In a rotor as set forth in claim 5, said body being formed with a plurality of axial bores therethrough terminating in said recesses and angularly spaced from each other relative to said axis, said plates being each formed with a plurality of apertures respectively aligned with said bores, and a rivet received in each bore and the aligned apertures of said plates, and fastening said plates to said body.

8. In a rotor as set forth in claim 7, respective integral annular portions of said plates projecting from the associated recesses in a radially inward direction and partly obstructing the associated orifices of said opening, the projecting portion of one of said plates constituting said gear rim.

References Cited UNITED STATES PATENTS 3,318,515 5/1967 Jones. 3,323,713 6/1967 Wenderoth et al 23145 3,400,604 9/1968 Jones 230l 3,400,939 9/1968 Jones 230 US. Cl. X.R. 

